When sending SOAP version 1.2 messages using the SaajSoapMessageFactory if no SOAP action is specified (using SoapActionCallback) then the message will still be sent with a "SOAPAction" header. The response will also have a "SOAPAction" http header. The "SOAPAction" header was replaced with the "action" parameter of the application/soap+xml MIME type in SOAP version 1.2. If a SoapActionCallback is used then the SOAP action is added in the appropriate place and the "SOAPAction" http header is removed, but that SOAPAction header should never be present for SOAP 1.2 messages. It appears the header is being added in the SaajSoapMessage constructor (around line 118 in master at the time the issue was created).